In 40 years, Emily will be 5 times as old as she is right now. How old is she right now?
Explanation: We can use the given information to write down an equation about Emily's age. Let Emily's age be $e$ In 40 years, she will be $e + 40$ years old. At that time, she will also be $5 e$ years old. Writing this information as an equation, we get: $e + 40 = 5 e$ Solving for $e$ , we get: $4 e = 40$ $e = 10$.